Exploring for and determining the presence and size of petroleum and other hydrocarbon deposits is conventionally expensive and time consuming. Locations where such deposits are suspected to exist are first identified and a drilling rig probes each suspected site. Such drilling is expensive, time consuming and the identification rate of viable deposits is extremely low.
Minimally invasive systems and methods for detecting petroleum and other hydrocarbon deposits are therefore desirable because such systems and methods may provide for substantially less expensive and faster exploration for energy resources. A greater number of candidate sites can be tested with substantially less cost than conventional drilling tests. Moreover, testing can occur at sites that may otherwise be inaccessible by bulky and cumbersome drilling equipment.
Such minimally invasive systems are known in the art for detecting underground features, but are deficient for a variety of reasons. For example, many of these systems to not provide accurate and reproducible data. Although many minimally invasive systems provide results that appear to show the location of underground features, these results are difficult to interpret and such interpretations are highly subjective. Accordingly, the results from many minimally invasive tests are speculative, error prone, and have an unacceptably high rate of false positives and false negatives.
Additionally, systems presently known in the art only provide satisfactory results at shallow depths, which make them useless for detecting below ground features that are below this depth range. This may be suitable for shallow water well detection, but given that the vast majority of petroleum and other hydrocarbon deposits are located at depths that are far below the operative depth of presently known minimally invasive testing systems, such systems that are presently known in the art are not a suitable solution for energy exploration.
For example, U.S. Pat. No. 5,903,153 to Clarke et al. teaches an apparatus and method for detecting underground liquids (known as electrokinetic, electroseismic and more recently seismoelectric sensing) in which electrical potential generated by a seismic shock is detected and measured with respect to a base point insulated from the earth. The disclosed electrokinetic (seismoelectric) system teaches remote sensing of water and other below-ground features. However, as depicted in FIG. 4, the Clarke system only has a maximum depth sensitivity less than 80 meters. In practice, commercial products using the Clarke system, and other minimally invasive sensing systems fail to have an operative depth range that exceeds the 80 meter maximum taught in the Clarke patent.
The Clarke system (and other systems like it) are not operable to detect below-ground features for many reasons. For example, such systems operate by ground level detection of signals generated by underground features. Because such signals become increasing attenuated as they travel upward from an underground source, detection of such signals originating from a deep source are typically masked by environmental and system noise. Accordingly, because these systems generate a signal-to-noise ratio that makes it impossible to discern deep-source signals, they do not operate with a gain that would allow them to detect weak deep-source signals, and do not record signals over a time period when deep-source signals would be received.
In view of the foregoing, a need exists for an improved seismoelectric ground feature sensing system and method for deep detection of petroleum and hydrocarbon deposits, in an effort to overcome the aforementioned obstacles and deficiencies of conventional ground feature sensing systems.
It should be noted that the figures are not drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the preferred embodiments. The figures do not illustrate every aspect of the described embodiments and do not limit the scope of the present disclosure.